Sure, tips of 21 cents filling up a thread can look spammy and seems cheap, but 10,000 tips of 21 cents is $2,100. People will be far more likely to tip their favorite YouTube channel 21 cents than anything over $5.
Micropayments look a bit ugly now, but people are responding very well because it is something they haven’t seen before, and clearly is something that cannot be done with other forms of payments. Changetip bots are spammy because people don’t know what it is and need to be informed what to do. Once it becomes more elegant, 32 cent tips won’t need to be broadcasted. The effects of micropayment will be profound, this is the first little taste.